The present invention relates to the field of flexible tubes, and more specifically to the heads of such tubes.
Flexible tubes are commonly formed by a tube head connected to a skirt, the tube head comprising a neck for removing a product contained in the tube, whereas the skirt forms the internal volume of the tube which is capable of receiving a product.
The skirt is conventionally formed by a multi-layer sheet adapted to have satisfactory mechanical strength and sealing properties.
The tube head is, however, commonly formed by plastics injection moulding, and this may prove to be unsatisfactory for certain applications owing to the highly reactive nature of certain products and to the penetration of certain gases and liquids into the tube, thereby altering the contents of the tube, or, on the contrary, owing to certain components of the contents of the tube leaking out, thereby leading to the product itself being degraded.
In order to solve this problem, several solutions have been proposed. In particular, it is possible to place an insert, or disc, in the region of the tube head, which insert is shaped to the inner face of the shoulder of the tube head, so as to form a protective barrier separating the tube head from the product contained in the tube. It thus allows the penetration and leakage of the undesirable components through the head of the tube to be limited, and protects the head of the tube and the contents of the tube. This insert typically comprises a metal layer and/or an ethylene-vinyl-alcohol layer (EVOH).
However, such tube-head structures are complex and costly to produce. In particular, it is difficult to position, in particular to centre, the insert so that the shoulder of the tube head is correctly protected. The insert does indeed need to be properly positioned, for example to prevent its peripheral end from being in contact with the contents of the tube, in particular in the case of metal inserts in order to limit the corrosion of the insert, for example. Incorrect positioning may also lead to significant plastic deformations of the insert and may reduce the barrier properties thereof. The prolonged periods of storage of the product may therefore lead to deterioration of the tube head and/or of the product.